Automatic pressure-retainer.



O. T. JOHNSON.

AUTOMATIC, PRESSURE RETAINER.

APPLICATION FILED MAY 12, 1911. 1,006,223, Patented Oct. 17, 1911.

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AUTOMATIG PRESSURE RETAINER.

APPLICATION FILED MAY12, 1911.

1,006,223. Patented 001111911.

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ORVAL T. JOHNSON, OF MURPHYSBORO, ILLINOIS.

AUTOMATIC PRESSURE-RETAINER.

Specification of Letters Patent.

Application filed May 12, 1911.

Patented Oct. 17, 1911.

Serial No. 626,876.

- To all whom it may concern:

Be it known that I, ORVAL T. JOHNSON, a citizen of the United States, residing at Murphysboro, in the county of Jackson and State of Illinois, have invented new and use ful Improvements in Automatic Pressure- Retainers, of which the following is a specification.

This invention relates to an automatic pressure retainer for air-brake systems, and its object is to provide a pressure retaining device whereby the exhaust of the triple valve is placed under the control of the engineer, so that the train line and auxiliary reservoirs may be recharged to normal pressure while the brakes are set, allowing a train in descending heavy grades to be held completely under control.

A further object of the invention is to provide a pressure retainer which is accurate and sensitive in action, simple and comparatively inexpensive of construction, and free from complicated parts liable to get out of order.

The invention consists of the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawings, in which Figure 1 is a view in elevation, showing the application of the invention. Fig. 2 is a sectional view through the retainer, show ing the parts in the position they assume after the application of the brakes and before the train line is recharged. Fig. 3 is a view similar to Fig. 2, showing the parts in brake-releasing position. Figs. 1 and 5 are sections on the lines 4-4 and 55 of Fig. 2.

The retainer comprises a pair of superposed cylinders 1 and 2, preferably made in a single casting, and disposed with their axes out of longitudinal alinement, but in parallel relation, as shown. The lower cylinder 1 is adapted to receive the exhaust of fluid pressure from the triple valve casing, and is provided at its lower end with a neck or reduced extension 3 through which extend air feed passages 4 and 5. The passage 4 communicates with the lower end of the cylinder 1, while the passage 2 extends upwardly through the side of the cylinder 1, base of the cylinder 2, and thence up through the side of the cylinder 2 to the top of said cylinder. The neck 3 is coupled by a suitable" sage 5 is in communication with a branch'i pipe 8 leading to the train line. In practice, the cylinders are preferably vertically arranged and are provided with flanges or suitable projections 9, whereby they may be bolted or otherwise fastened to the locomotive or railway car to which the device is to be applied.

The passages 41 and 5 are controlled at their inlet ends by a plug valve 10 provided with ports 11 and 12 for communication therewith, whereby the retainer may be thrown into and out of action whenever desired. In the connection 6 is a valve 10 which is open, when the valve 10 is closed to out out the retainer, to permit free exhaust from the brake cylinder to the atmosphere.

Arranged for movement within the cylinder 1 is a piston valve 13, of proper weight to be raised at about twenty pounds pressure, the usual pressure of the exhaust from the triple valve. This piston valve is fixed upon the lower end of an upwardly extending stem 14 which is slidably mounted in the upper head of said cylinder and in a guideway 15 formed in the wall of the cylinder 2. In said piston valve is formed an angular passage 16 having its inlet end opening through its base for connection with the cylinder below said valve and its exhaust end opening through the periphery of the valve Surrounding the upper end of the stem 14 and supported by the upper head of the cylinder 1 is a coiled cushioning spring or Arranged within the cylinder 2 is a piston or head 19 which is subjected to the force of the train line pressure entering said cylinder through the feed passage 5. From this piston head depends a stem 20 slidably mounted in the lower head of said cylinder 2 and in a longitudinal guide way 21 formed in the side of the cylinder 1 in parallel relation to the feed passage 5, which guide way 21 is in communication with the port 17 and with a final exhaust port 22 leading to the atmosphere. The stem 20 operates as a valve controlling the port 17, and is provided with a port or opening 23 therethrough adapted to register with said port 17 when the piston 19 is depressed to its limit, whereby the fluid pressure is permitted to exhaust from the cylinder 1 to the atmosphere. A spring 24 is carried by the portion of the stem movable in the guideway or passage 21, and operates to hold said stem in close contact with the surface of the wall in which the port 17 is formed to prevent leakage. The piston head 19 is normally sustained by a coiled spring 25 surrounding the stembetween said piston head and the lower end of the cylinder 2, which spring is of proper strength to hold the piston head against downward movement until the pressure in the train line has reached the normal degree, approximately seventy pounds.

In the operation of the retainer, it will be understood that the retainer on each locomotive or car may be cut out of service whenever required by closing the valve 10 and thrown into operation at any time by opening said valve, whereby communication will be established between the exhaust port of the triple valve and the cylinder 1 and between the passage 5 and the train pipe. As the weight of the gravity piston valve 13 is such as to require a pressure of at least twenty pounds to elevate it, it will be apparent that it will maintain its normal position at the lower end of said cylinder until the pressure of the exhaust from the triple valve is sufficient to raise it to bring the passage 6 into registry with the exhaustport 17. If, under such conditions, the pressure in the train line is below normal, the exhaust of fluid pressure from the triple valve will be prevented through the closure of said port 17 by the valve stem 20, so that the brakes will be held set or applied. The engineer may, therefore, recharge the train pipe and auxiliary reservoir until the pressure in the train line reaches the normal, whereupon the piston 19 will be depressed against the resistance of the spring 25 until the port 23 registers with the port 17, whereupon the exhaust from the triple valve will vent to the atmosphere through the port 23. As a full pressure of air is now in the brake system, it will be understood that the engineer may again immediately apply the brakes if desired. Hence, it will be seen that the pressure in the brake cylinder may be maintained while the train line is being recharged, giving the engineer thorough and complete control over the train in descending heavy grades.

Having thus described my invention, I claim 1. A pressure retainer comprising a pair of cylinders provided with passages for respective communication with the triple valve exhaust port and the train line of an air brake system, one of said cylinders being provided with an exhaust port, a piston valve movable in said cylinder under the pressure of air from the triple valve and provided with a passage to register with said exhaust port, a downwardly movable piston in the other cylinder provided with a stem cont-rolling said exhaust port, and a spring arranged to prevent depression of said piston until the pressure in said cylinder reaches a predetermined degree.

2. An automatic pressure retainer for air brake systems comprising an exhaust cylinder and a controlling cylinder, said exhaust cylinder being provided with an exhaust port and a passage for communication with the triple valve exhaust, and said controlling cylinder being provided with a passage for communication with the train line, an upwardly movable piston valve in the exhaust cylinder having a port to register with said exhaust port and provided with a guide stem movable in guide ways in said cylinder, a downwardly movable piston in the controlling cylinder provided with a depending stem movable in guide ways in said cylinder and having an opening to register with said exhaust port, and a spring arranged to oppose depression of said piston until the train line pressure thereon reaches a predetermined degree.

'3. An automatic pressure retainer for air brake systems comprising an exhaust cylinder having an exhaust port and a feed passage for communication with the exhaust port of the triple valve, a controlling cylinder provided with a feed passage for communication with the train line, said cylinders being depressed in superposed relation and provided with guide ways, a piston valve in the exhaust cylinder movable upwardly under fluid pressure and provided with a port to register with said exhaust port, a stem projecting upwardly from said valve and movable in one of said guide carried thereby and movable in the other guide way, said stem being provided with a port to register with the exhaust port, a

pressure spring for guiding said stem in a In testimony whereof I aflix my signature true path, andba spring inclosing the stelrln in presence of two witnesses.

and dis osed etWeen said iston and t e lower er id of said controlling cylinder and ORVAL N operating to oppose a determined resistance Witnesses:

to the movement of said piston head under Mrs. F. G. BIEBER,

the train line pressure thereon. ELLA BIERER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

